High Voltage Power Supply for POLAR –
Space Based GRB Polarisation Detector

POLAR on the orbit

The Tiangong-2 orbital module with detector POLAR on board has been launched
from the Jiuquan Satellite Launch Center
on 15 September 2016 at 14:04 UTC (16:04 polish time). POLAR will measure polarisation
of photons from Gamma Ray Bursts.

X-ray polarisation measurements of Gamma Ray Bursts may provide important information
about the emission processes. These very energetic astrophysical events are also candidates
for ultra high energy cosmic ray sources.

In the middle of 2011 we were asked to design, develop and produce a functional model
of a high voltage power supply for 25 MAPMTs. The goal was to provide individually
adjustable high voltage to every MAPMT, retain the redundancy required in space
experiments, make power efficient device, provide the opportunity to measure some
actual performance and finally fit the allocated space and weight. From the 3
different solutions we proposed one was selected for development.

The basic idea was to generate one high voltage (-700V – -1100V) below any required
level by MAPMTs, and reduce it for each MAPMT to an individual level. Each MAPMT
has a resistance divider to distribute voltages to cathode, dynodes and grid. We
propose to use current sources to reduce the current individually on each divider,
and this way to provide a cathode voltage equal to the product of this current and
the divider resistance.

At the beginning of 2012 we provided a HVPS engineering model, a simple controller
and HV-board for tests of HVPS performance to the University of Geneva, the leading
institution of the POLAR experiment.